Enhanced strain hardening induced by twin boundary-dislocation interaction in micro-pillar compression of CoCrNi medium-entropy alloy

In this contribution, we compare the mechanical behaviors of single crystal micro-pillars of CoCrNi medium-entropy alloy with and without deformation twins during compression test. It is found that the micro-pillar with deformation twins maintains higher increment of flow stress as compared to the one without deformation twins. The enhanced strain hardening behavior is ascribed to the substantially increased dislocation density resulted from the intensive twin boundary-dislocation interaction. The present study evidences the critical role of deformation twinning in the improved work hardening behavior of twinning-related deformation mechanism of alloys with low stacking fault energy such as CoCrNi.